×
Get Full Access to Statistics For Engineers And Scientists - 4 Edition - Chapter 2 - Problem 11se
Get Full Access to Statistics For Engineers And Scientists - 4 Edition - Chapter 2 - Problem 11se

×

# There are two fuses in an electrical device. Let X denote

ISBN: 9780073401331 38

## Solution for problem 11SE Chapter 2

Statistics for Engineers and Scientists | 4th Edition

• Textbook Solutions
• 2901 Step-by-step solutions solved by professors and subject experts
• Get 24/7 help from StudySoup virtual teaching assistants

Statistics for Engineers and Scientists | 4th Edition

4 5 1 385 Reviews
11
2
Problem 11SE

There are two fuses in an electrical device. Let X denote the lifetime of the first fuse, and let Y denote the lifetime of the second fuse (both in years). Assume the joint probability density function of X and Y is

$$f(x, y)= \begin{cases}\frac{1}{6} e^{-x / 2-y / 3} & x>0 \text { and } y>0 \\ 0 & \text { otherwise }\end{cases}$$

a. Find $$P(X \leq 2 \text { and } Y \leq 3)$$.

b. Find the probability that both fuses last at least 3 years.

c. Find the marginal probability density function of X.

d. Find the marginal probability density function of Y .

e. Are X and Y independent? Explain.

Equation Transcription:

Text Transcription:

f(x,y)={_0     otherwise^{1over 6}e^{-x/2-y/3}     x>0 and y>0

P(X2 and Y3)

Step-by-Step Solution:

Solution:

Step 1 of 4 :

There are two fuses in an electrical device . Let X denote the lifetime of the first fuse, and let Y denote the lifetime of the second fuse (both in years). And the joint probability density function of X and Y is

We have to find

1.  P(X ≤ 2 and Y ≤ 3).
2. The probability that both fuses last at least 3 years.

1.   The marginal probability density function of X.

1.   The marginal probability density function of Y.

1.   Check X and Y are independent.

Step 2 of 4

Step 3 of 4

## Discover and learn what students are asking

Calculus: Early Transcendental Functions : Preparation for Calculus
?In Exercises 5–8, test for symmetry with respect to each axis and to the origin. $$y=x^{2}+4 x$$

Statistics: Informed Decisions Using Data : The Design of Experiments
?Explain the difference between a single-blind and a double- blind experiment.

Statistics: Informed Decisions Using Data : Comparing Three or More Means (One-Way Analysis of Variance)
?In Problems 7 and 8, fill in the ANOVA table.

Statistics: Informed Decisions Using Data : Inference about the Difference between Two Medians: Dependent Samples
?Rats’ Red Blood Cell Counts Researchers at NASA wanted to learn the effects of spaceflight on a rat’s red blood cell count (RBC). The following data r

#### Related chapters

Unlock Textbook Solution